Terpenes Attract Pollinators
One of the main abilities that plants have to focus on is reproduction and getting pollinated. If a species is to live on it has to find ways to ensure it gets pollinated successfully to ensure it survival. Fungi and animals use a variety of methods to accomplish this and while there are plants that reproduce usually, some species rely purely on being pollinated to produce fruits and seeds. That’s why some plants work very hard to attract pollinators like bees, butterflies, birds, small mammals, etc.
While some plants use vibrant colors to attract pollinators, some of them actually rely on terpenes to lure in specific pollinators.
A study has shown that kiwifruit depends highly on bees to transfer pollen from male and female plants. The study by the Journal of Experimental Botany found that terpene levels varied throughout the day, and between male and female plants, to attract bees. “Previously, it has been shown that α-farnesene and germacrene D are involved in the attraction and conditioning of honeybees and other insects. Indeed, emission of these terpenoids, as well as (E)-β-ocimene over a light/dark cycle occurs during the daytime when potential pollinators are active” (1).
They even concluded, “This work reinforces the importance of volatile terpene cues for insect pollinator attraction and conditioning, a requirement for efficient pollen transfer between the staminate and pistillate plants, and ultimately the survival of any dioecious species.”
Repelling Insects and Herbivores
Just like it is important to be able to reproduce for plants' survival, it is equally important to be able to defend themselves against certain predators and insects.
Some terpenes are toxic to herbivores, while other terpenes influence the reproductive system of insects. The former encourages animals to avoid the said plant, while the latter makes it harder for insects to infest a plant. Both options make it much more likely that a plant species will survive.
There are even some chemicals that attract certain insects specifically so they’ll attack or eat any insect infestations. “Attracting predators or parasitoids is an effective indirect defense adopted by plants against herbivores.” For example, cabbage plants can become infected with the insect Pieris brassicae (a type of caterpillar). However, cabbage plants also attract another insect that actually lays eggs inside those caterpillars, effectively ending the infestation.
Terpenes Can Protect Plants From Sun Damage
While sunlight is necessary for photosynthesis, too much sunlight and/or heat can be damaging to plants in this case certain terpenes act to protect the plant from UV rays
Linalool, in particular, has been known to increase or decrease in concentration depending on how much sun exposure a plant gets. This helps protect plant tissue from UV rays. There are even some terpenes that absorb UV rays and act as antioxidants. That means they function almost like sunscreen while providing additional protection against the effects of UV rays. So, if you’ve ever wondered why so many sun protection products have Limonene, this is why!
Terpenes Can Protect Plants From Pathogens
Bacteria, viruses, and various microorganisms can all cause serious diseases in plants. Like us, plants have immune systems that help them overcome pathogens.
“Many plant-associated microbes are pathogens that impair plant growth and reproduction. Plants respond to infection using a two-branched innate immune system. The first branch recognizes and responds to molecules common to many classes of microbes, including non-pathogens. The second responds to pathogen virulence factors, either directly or through their effects on host targets” (4).
Plantsimmune systems use terpenes to help destroy or overcome these pathogens. When the surface receptors of a plant detect certain pathogens, the plant immune system begins a series of responses. The plant will release proteins, oxidases, and terpenes to attack and destroy pathogens.
What’s more, terpenes are important for providing this protection to an entire area. Essentially, plants use terpenes to tell other plants that it’s time to prep their immune responses because a pathogen is nearby.
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